Want to use Arduino in my truck for various projects. Keep reading horror articles about the '12v' power available.
Since 14v+ is normal when charging and Arduino maxes at 12v, could I use a resistor to lower voltage to 6v and a Max809 chip to filter noise. This would seem to be a low cost way for protection,

I am a novice on reading circuits much less design.

Thanks for any advice.

 

No to R.

In general you have to deal with load dump in a vehicle.

https://en.wikipedia.org/wiki/Load_dump

https://www.onsemi.com/pub/Collateral/LM2931-D.PDF


Regards, Dana.

 

A resistor is NOT a good idea. It won’t have a reliable output as the Arduino current draw changes. You need a circuit to regulate the voltage.

Look into a DC to DC converter with a well-filtered 5VDC output. Then power the Arduino through the Vin pin. This bypasses the onboard regulator. That’s where the 12VDC limit is.

 

LM7805 works well if you want to build something or make the atmega chip stand alone but for just basic powering of an arduino you could pretty much use any usb adapter like what your phone uses.

 

Thanks for comebacks. I didn't think about load changes with resister.
I am out of state right now - I will try to digest the 2 'regulators' when I get home.
I am trying to build a device to control lights. I have the code running on uno with led's for testing.
I am thinking about using a solid state relay to handle current.
I will try to containerize later.


Again thanks

 

If you trying to use 14V or 14.2V to plugin to the arduino power jack(7~12V), probably you can in series with 4 1N4001 and plugin to the power jack.

 

I looked at the TI LM7805CT/NOPB device for suppling power. It puts out 5v and will work in a hot environment like a car - also less than$2. I looked at the TI TPS1H100-Q1 for switching the 12v+ to the bulbs but got quickly lost at the numerous connection points

 

Want to use Arduino in my truck for various projects. Keep reading horror articles about the '12v' power available.
Since 14v+ is normal when charging and Arduino maxes at 12v, could I use a resistor to lower voltage to 6v and a Max809 chip to filter noise. This would seem to be a low cost way for protection,

I am a novice on reading circuits much less design.

Thanks for any advice.

Most types of PSU applicable to this have a series pass semiconductor that would dump the input voltage to the load if it fails.

A flyback type driving a stepdown transformer is more or less fail-safe.

I'd probably go the lazy route - a dirty great shunt regulator and current limiting resistor. They're very inefficient but they effectively shut down if the semiconductor fails.

A big enough Zener diode might not be easy to find, but you can boost it with a transistor. The TL431 application note gives a pretty good idea how to do this, and the 431 programmable Zener makes it easy to trim out the Vbe loss on the boost transistor.

 

About the easiest way (but not the cheapest) is hack a USB charger you plug in to your car. Usually they will put out one or two amps, but a little looking could find a higher power unit. I used one on a project for a few years before a loose ground wire killed it. They have some circuitry to handle load dumps and such already built in. The downside... they cost a little more, they will take some custom mounting, and wiring them up can be tricky depending on how they were built.

If you want to use your analog to digital converters you may need some more filtering depending on how cheap the charger was built so it may be better to go with a custom made power supply in that case.

 

ian field you are way over my head.

I will try to produce a drawing of what I think I now know sometime this week.

 

If this device has a LM2596HS chip, then it can withstand 63 Volts on the Input.
Adjust the output to 7 Volts before connecting to the Arduino
It can handle 3 amps max
Operating temperature -45° C to +85°C
Ripple = <30mv
$5.00
https://www.ebay.com/itm/LM2596HVS-...ck-Converter-Power-Supply-Module/253940109792

The Voltage Regulator on-board the Arduino will provide additional filtering & final regulation

 

If this device has a LM2596HS chip, then it can withstand 63 Volts on the Input.
Adjust the output to 7 Volts before connecting to the Arduino
It can handle 3 amps max
Operating temperature -45° C to +85°C
Ripple = <30mv
$5.00
https://www.ebay.com/itm/LM2596HVS-...ck-Converter-Power-Supply-Module/253940109792

The Voltage Regulator on-board the Arduino will provide additional filtering & final regulation

Use automotive spike suppressors on the input and an SCR crowbar protection on the output. A fuse might come in handy too...……..

 

When researching to do drawing I was seeing a npn transistor driving a pnp transistor or other device for high side switching. Thus adding another component.
Then I found another TI device - the TSP1H000-Q1. IT seems to be built to be controlled directly by a microprocessor.
See http://www.ti.com/document-viewer/TPS1H000-Q1/datasheet/features-x5241#x5241 .
This device as well as the LM7805 are built for the auto environment.

 

Can find any info if the TSP1H000-Q1 can be directly connected to Arduino. Joined TI user forum and posed that question.